The UK Supreme Court has dealt a further blow to Prime Minister Theresa May, ruling that the Scottish and Welsh governments can intervene in the Brexit process.

The Supreme Court ruled Friday that Edinburgh and Cardiff can seek their right to have a say in the triggering of Article 50 of the Lisbon Treaty, the formal process for starting Brexit, according to The Independent.

The move threw a further hurdle in the way of May’s hopes of a smooth Brexit, raising the possibility of the Supreme Court agreeing with the Scottish National Party (SNP) that it should have the right of veto over the Brexit strategy.

The ruling seems to be a big victory for Nicola Sturgeon, the SNP’s first minister, who has sought to enable Scotland to play a role in Brexit after the country voted decisively to remain in the European Union.

On June 23, nearly 52 percent of British people voted to leave the bloc, after 43 years of membership, a decision that sent shockwaves throughout the world.

May leaves 10 Downing Street in London on November 16, 2016. (Photo by AFP)

May later said she would start the process by March 2017 and bring it to completion in two years. She also said that the British parliament would not vote on triggering the EU divorce, but a debate could be held over the government’s Brexit plan.

However, the UK High Court ruled last month that Brexit should be approved in the Parliament too, delaying May’s plans to begin the process.

Following the ruling, May urged the UK Parliament to accept the Brexit vote, saying the MPs must allow the government to carry out its plan.

“It was MPs who overwhelmingly decided to put the decision in their hands. The result was clear. It was legitimate. MPs and peers who regret the referendum result need to accept what the people decided,” she said earlier this month.

May has also been under pressure by some politicians to pursue the so-called hard Brexit, which suggests surrendering access to the EU’s single market and scrap free movement of EU nationals in return for securing control over immigration.